Please define what you mean by a pro camera? What makes it different? The person using it or the camera? If a pro uses the DF does it then become a pro camera?

If you're going to take the term "pro" seriously, Nikon makes just one pro DSLR and it's the D4.

I own the D800 and Df, but the D4 is simply the top tier and clearly pro, starting with it's size and handling and ending with it's FPS.

The D800, Df, D610 are NOT in the same league overall though their owners like to chant otherwise.

With that said, only gear heads and armchair shooters worry about such terms and nonsense. Some amazing work is done with D5100 and far less "pro" bodies.

The pro is about the person shooting, not the camera. Generally there are there levels:

1) Pro - the person who makes money with the gear. This person buys what's needed and usually could care less about some bozo's assessment of what his gear is. It has to do the job: end of story. D4, Df, or a D3100. If it makes money, that's all that matters. Very few pros give a hoot about such things.

2) Hobbyist - Family shooting, vacation, and everything in between, but usually not a devoted artist. This is the group most likely to assign some sort of status to their gear and lenses. Believing they have pro gear might be important, though they can rarely make use of it.

3) Artist - Not always shooting for money and sometimes the best/most talented of the three, this person is also not interested about silly gear hierarchy. The final image is what it's all about. The Df might appeal to them as would a D800.